Brenner Base Tunnel: The next Challenge for mechanized Tunnelling

Quelle/credit: BBT SE

Geology along the Brenner Base Tunnel varies widely and includes a major fault zone where the European and Adriatic tectonic plates press together

Quelle/credit: BBT SE

The segment lined 6 km long exploratory bore to determine the geology underlying the Brenner Pass in the Alps Mountain Range

Quelle/credit: BBT SE

Quelle/credit: Robbins

Recommended ground support for high cover tunnels in loose and stressed rock includes yieldable elements such as rock bolts and channel straps

Quelle/credit: Robbins

Quelle/credit (3): Robbins

In loose and stressed rock, combinations of ground support can be used such as yielding rock bolts, channels, McNally slats, and wire mesh

Quelle/credit (3): Robbins

Quelle/credit: Robbins

A Robbins Main Beam Machine was launched in 2007 to bore Peru’s Olmos Trans-Andean Tunnel, the world’s second deepest civil works tunnel, below 2000 m of rock

Quelle/credit: Robbins

Crews survey damage after one of more than 16 000 recorded rock bursting events in Peru’s Olmos tunnel

Quelle/credit: Robbins

Steel McNally slats in the tunnel crown successfully contain a rock bursting event at Peru’s Olmos Tunnel

Quelle/credit: Robbins

The oft-mentioned Brenner Base Tunnel is Europe’s next mega-rail project in the making. Including the Innsbruck bypass, the 64 km long tunnel route will run from Innsbruck, Austria to Fortezza, Italy, making it arguably one of the longest – if not the longest – underground railway tunnels in the world. The tunnel route is a challenging one, traveling below the Brenner Pass in the Alps mountain range with a maximum cover of around 1600 m. When complete in 2025, twin 8.1 m i.d. tubes will run single-track trains just 70 m apart from one another, connected every 333 m by cross passages.

The authors of this article believe that the best methods for excavation of the Brenner Base Tunnel are mechanized – specifically using either open-type or shielded hard rock tunnel boring machines. These types of machines have proven themselves in deep tunnels worldwide, and are frequently faster, safer, and more cost-effective than conventional drill & blast headings. Obviously, the use of specialized ground support to adapt to the challenging rock condition will have to be integrated into the TBM design and operation as well.